[Intel-gfx] [PATCH v2] drm/i915: Fake HDMI live status

[Jani Nikula]

On Thu, 21 Apr 2016, Shashank Sharma <shashank.sharma at intel.com> wrote:
> This patch does the following:
> - Fakes live status of HDMI as connected (even if that's not).
>   While testing certain (monitor + cable) combinations with
>   various intel  platforms, it seems that live status register
>   doesn't work reliably on some older devices. So limit the
>   live_status check for HDMI detection, only for platforms
>   from gen7 onwards.
>
> This fixes regression added by patch:
>   'commit 237ed86c693d ("drm/i915: Check live status before reading edid")'

Fixes: 237ed86c693d ("drm/i915: Check live status before reading edid")
Cc: stable at vger.kernel.org # v4.4

>
> V2: restrict faking live_status to certain platforms
>
> Based on suggestion by: Ville Syrjala<ville.syrjala at linux.intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index b199ede..c2150db 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1412,8 +1412,16 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
>  				hdmi_to_dig_port(intel_hdmi));
>  	}
>  
> -	if (!live_status)
> -		DRM_DEBUG_KMS("Live status not up!");
> +	/*
> +	* Live status reg is not reliable for all older platforms
> +	* So for certain platforms, dont block EDID read even if
> +	* live_status is down, give EDID a shot.
> +	*/
> +	if ((INTEL_INFO(dev_priv)->gen < 7 || IS_IVYBRIDGE(dev_priv))
> +		&& !live_status) {
> +		DRM_DEBUG_KMS("Warning: live status not up, faking it\n");
> +		live_status = true;
> +	}
>  
>  	intel_hdmi_unset_edid(connector);

-- 
Jani Nikula, Intel Open Source Technology Center